Vectra LCP

Injection molded thermoplastic bipolar plates made of Vectra LCP (liquid crystal polymer) and Fortron PPS fabricated by Ticona Engineering Polymers, (http //www.ticona.com/redesign/ index/markets/innovation/fuel cell.htm Ticona Engineering Polymers. 2008 accessed March 2008.)... 

Vectra LCPs consist of parallel, closely packed, fibrous chains in injection molded parts which give the polymer a wood-like appearance at fracture surfaces and also give it seU-reinforcing properties that are at least as good as those of conventional fiher-reinforced thermoplastics. ICI supphes LCPs (self-reinforcing polymers) under the trade name Victrex SRP. Excellent physical properties, low comhnstihility and smoke generation, resistance to chemicals and solvents, and stahihty towards radiation are some of the important properties of LCPs. 

Figure 4.119 Shear modulus vs. temperature for various Celanese Vectra LCPs.

Figure 4.120 Tensile modulus vs. temperature for Celanese Vectra LCP [9],...

Figure 4.126 Dampening factors vs. temperature by dynamic mechanicai anaiysis of Ceianese Vectra LCPs [9].

Figure 4.130 Dielectric constant vs. frequency at 23°C for various Ceianese Vectra LCPs.

Rigid-chain polymers containing different concentration of laterally attached side rods have been demonstrated in bulk reactions using a Vectra LCP as the base material, as illustrated in Figure 3 (57). These polymers exhibit liquid crystallinity even up to a maximum side-rod concentration of 20 mol%. The crystallinity of the... 

Specifically, Celanese has defined families of thermotropic polyesters derived from 2,6-naphthalene dicarboxylic acid (NOA), 2,6-dihydroxynaph-thalene (DHN) or 6-hydroxy-2-naphthoic acid (HNA). Indeed, the Vectra LCP engineering resins of Celanese Corporation are based on these monomers. 

Thermotropic aromatic copolyester fibers are produced by melt spinning since the combination of an aromatic backbone and flexible segments results in an LCP which can be melt processed. Copolyesters, such as p-hydroxybenzoic add (PHBA) modified poly(ethylene terephthalate) (PET), 60/40 PHBA/PET (X7G) polymers, have been produced by the Tennessee Eastman Company [425-427]. Other melt processable nematic thermotropic LCPs (TLCP), based on combinations of 2,6-naphthalene dicarboxylic add (NDA), 2,6-dihydroxynaphthalene (DHN) and 6-hydroxy-2-naphthoic acid (HNA), and referred to as Vectra LCP resins, have been conunercialized (trademark by Hoechst Celanese Corporation [406]). 

Polymers are nsed in fnel cells. Those of particular interest are the polymer electrolyte membrane (PEM) and the phosphoric acid fuel cell (PAFC) designs. The latter design contains the liquid phosphoric acid in a Teflon bonded silicon carbide matrix. In March 2005 Ticona reported that it had bnilt the first fnel cell prototype made solely with engineering thermoplastics. They claimed that this approach rednced the cost of the fuel by at least 50% when compared with fuel cells fabricated from other materials. The 17-cell unit contains injection moulded bipolar plates of Vectra liquid crystal polymer and end plates of Fortron polyphenylene sulfide (PPS). These two materials remain dimensionally stable at temperatures up to 200 "C. The Vectra LCP bipolar plates contain 85% powdered carbon and are made in a cycle time of 30 seconds. 

Coil formers, which carry windings in inductors, motors and transformers, must be tough and able to withstand the temperatures experienced. Polymers used include Vectra LCP, PBT, PC, PA and phenolic resins. 

Vectra LCP, Hoechst Verton Long fiber composites, LNP Vcspel Polyimide parts and shapes, DuPont... 

In late 1985 Hoechst Celanese commercialized a family of LCPs under the trademark Vectra. Based on hydroxybenzoic acid and naphthalene derivatives, like Xydar , Vectra LCP exhibits a nematic structure. Although Xydar and Vectra are classified genetically as wholly aromatic polyesters with similar basic structures, it is important to note that many of the characteristics of the LCP polymer systems vary significantly with their chemical compositions. Other companies that are commercially active include Sumitomo Chemical, Mitsubishi Chemical, Ueto and Unitika. 

Table 7.7 Electrical and flammability properties of Vectra LCPs... 

Table 7.13 Part CTE versus moulding conditions for Vectra LCP variants...

Table 7.14 Environmental test results for Vectra LCP-moulded coupler...

Figure 6.76 Dynamic coefficient of friction for various Celanese Vectra LCP resins (P = 6 N, v = 60 cm/min) [19].

Table 6.24 Coefficients of Friction for Various Celanese Vectra LCP Grades [19]...

Vectra LCP Grade Coefficient of Friction—Flow Direction ... 

In 2002, Ticona engineering polymers doubled capacity of its Vectra LCP plant at Shelby, North Carolina, USA, to 6,000 tpa. The company also produces LCP in Fuji City, Japan, in cooperation with 45% affiliate Polyplastics Co Ltd (a joint venture with Daicel Chemicals Industries). In 2000, Polyplastics increased capacity for Vectra by 2,000 tpa of neat polymer, lifting its annual output to 8,000 tpa of neat polymer or 12,000 tpa of compounds. 

---